WELL ROUNDER Russian patent published in 2012 - IPC E21B7/28 E21B10/26 

FIELD: mining.

SUBSTANCE: well rounder comprises a jet nozzle, which is inserted into a circular piston, closing a side hole, capable of limited displacement to the bottom and opening of the side hole, besides, the circular piston is equipped with a controller downstream the jet nozzle, and this controller moves fixedly and longitudinally inside the circular piston, besides, a compression spring is installed on top of the controller, which presses the jet nozzle at the bottom, at the same time the additional piston is made in the form of a corrugated membrane installed oppositely to the side channel in the hydraulic chamber, sealed at the ends, filled with oil at the side of the casing and made as capable of moving the pusher down under excessive pressure at the side of the side hole.

EFFECT: expanded area of application due to operation of heavy drilling agents, due to insulation of a stop mechanism against ingress of a drilling agent, and also possibility to control a liquid flow, at which the stop mechanism actuates, and drilling bits move into the working position.

3 dwg